Biphenylene-graphene van der Waals bilayer heterostructure as an anode material for Li-ion batteries

Abstract

The quest to discover a top-tier electrode material for lithium-ion secondary batteries continues to advance for the past many decades in order to satisfy the surging power necessities. Pristine two-dimensional nanolayer electrodes often face challenges such as poor cycling efficiency, slow diffusion, and low lithium capacity. Fabricating heterostructure bilayers from different two-dimensional materials is a compelling approach to combine their inherent attributes while mitigating the individual drawbacks of each material. Current research work showcases a thorough investigation of the biphenylene-graphene (BPN/G) van der Waals bilayer heterostructure through first-principles calculations, aimed at evaluating its viability in the role of lithium-ion battery anode. The BPN/G bilayer exhibits robust energetic and thermal stability, coupled with excellent electronic and ionic conductivity . The binding energy of lithium for BPN/G bilayer is calculated to be −0.97 eV, illustrating a significant improvement over that of the individual monolayers. Lithium atoms preferentially adsorb into the interlayer region initially and later occupy the outer surfaces. The bilayer achieves saturation to reach its maximum lithium storage capacity of 956 mAhg −1 , surpassing that of pure graphene. The diffusion energy barrier for lithium migration along various pathways varies from 0.47 eV to 0.26 eV. The low barrier and high diffusivity of 3.9 × 10 −5 cm 2 /s, points toward high lithium mobility and excellent cycling efficiency. The BPN/G bilayer provides a beneficial operating voltage of 0.51 V, signifying stable cycling performance and safe operation. The outcomes indicate a high lithium storage capability, remarkable conductivity, smooth lithium mobility, and efficient voltage profile, validating the BPN/G bilayer as an ideal negative electrode component for lithium-ion secondary batteries.

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